Recording apparatus having a device for detecting the presence or absence of a liquid

ABSTRACT

A device for detecting the presence or absence of a liquid, which is installed on an ink-jet recording apparatus, is configured to determine the presence or absence of ink in the ink flow path by detecting the reflection of light from a light transmission portion by irradiating light thereon. The light transmission portion is formed on at least a part of the ink path wall that forms the ink flow path for supplying ink to the recording head. As a result, it becomes possible for responding to consumer demands of designing a smaller version of the ink tank, a cost effective production thereof, and the like in addition to provide images with excellent image qualities.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ink-jet recording method, an ink-jetrecording apparatus, an ink tank to be removably mounted on suchapparatus, and an ink-supplying means for supplying ink to the ink tank,which make possible to obtain a high-quality image on a recordingmedium. In addition, the present invention also relates to recordingsystems including a copying machine, a facsimile, and a printer, andalso a word processor and a personal computer integral with a recordingdevice, and a recorded material provided as a recording medium on whichan image is recorded by the recording apparatus.

2. Related Art

Heretofore, ink-jet recording apparatuses have been used as output meanson the commercial basis, for example they have been used as printers asoutput means of recording systems such as output devices of copyingmachines, facsimiles, electronic typewriters, and word processors,output terminals of work stations, and the like, and also such as handy-or portable-type printers equipped in information-processing systemssuch as personal computers and host computers, optical disk apparatuses,video apparatuses, and so on. In these cases, each of the ink-jetrecording apparatuses is configured to meet a specific function, a usagepattern, and the like of the corresponding apparatus.

As a general ink-jet recording apparatus, it has been known that onecomprises a recording device (recording head), an ink tank for storingink to be supplied to the head, a sheet-feed device for feedingrecording paper, and a control device to control these devices. Therecording head that discharges ink droplets from a plurality of nozzlesis serially moved or scanned in a direction (main-scanning direction)perpendicular to a direction of feed (sub-scanning direction). Theink-recording head performs a recording movement, in which the recordingpaper is intermittently fed a distance equal to the recorded widthduring non-recording intervals. In the case of a configuration of theink-jet recording apparatus that uses an on-demand type recording headby which ink is ejected onto the recording paper according to recordingsignals, it has been widely used because of the advantages of lowrunning cost and quietness. In the case of a configuration of theink-jet recording apparatus that uses a full-line type recording head inwhich a plurality of nozzles for ejecting ink is arranged linearly inthe sub-scanning direction, the recording head need only scan therecording paper once to perform recording of a width corresponding tothe number of nozzles. This makes for increased speed of recordingoperation.

The supply supply of ink deteriorates in quality when the remainingquantity of ink in an ink storage member such as the ink tank describedabove is lower than a predetermined level. As a consequence, a poorprinted output may be obtained and so high-quality image formationbecomes difficult. If the tank becomes completely empty of ink,furthermore, an image cannot be formed on the paper while ink-ejectingmeans of the recording head is driven in spite of the absence of ink. Inthis case, therefore, the possibility exists of causing a failure of theink-ejecting means. Especially in the case of using a heater forejecting ink, as is described later, the possibility exists ofdestroying the whole structure of the recording head by the effect ofabnormal heat-up. Conventionally, therefore, ink-jet recordingapparatuses have a device for detecting the presence or absence of aliquid (hereinafter, also referred as a liquid-detecting device), asshown in FIG. 1.

The liquid-detecting device shown in FIG. 1 comprises a cylindrical rod1001, a light source 1003 connected with the rod 1001, and alight-receiving unit (i.e., a photosensor). In this kind of the deviceconfiguration, the rod 1001 is in the type of having light transmissionproperties and also having a tip portion which is cut in a slantingdirection. As shown in the figure, the rod 1001 is arranged in an inktank 1002. The light source 1003 emits light toward a bottom of the inktank 1002 through the tip portion of the rod 1001. In the case that thedistance between the tip portion of the rod 1001 and the bottom of theink tank 1002 is kept at a constant, the following conditions can beobserved:

the condition that the tip portion of the rod 1001 is immersed in ink I(e.g., ink level is indicated by a solid line A higher than the tipportion);

the condition that there is a space between the tip portion of the rod1001 and ink level (e.g., ink level is indicated by a solid line A'lower than the tip portion); and

the condition of empty out the ink tank 1002.

Under each of these conditions, reflected light having its ownrefractive index can be detected. Therefore, through the use of thedifferences in refractive indexes under the above conditions thepresence or absence of ink can be determined by detecting whether theink level is positioned between the tip portion of the rod 1001 and thebottom of the ink tank 1002. Thus the photosensor 1004 receives thereflected light passing through the tip portion of the rod 1001, andthen the condition of the remaining quantity of the ink is determined bythe control unit 1005 connected with the photosensor 1004. If thecontrol unit 1005 makes a decision that the remaining quantity of theink is lower than the predetermined quantity, the operator is instructedto change or fill the ink tank by means of an indicator on an operationpanel (not shown) which is electrically connected to the control unit1005.

However, in accordance with the conventional ink-detecting methoddescribed above, light emitted from the light source 1004 is reflectedat an inner peripheral side wall of the rod 1001, so that it isdifficult to keep a constant incidence angle of reflected light againsta slant portion of the rod 1001 does not remain constant. It results inthe problem that the difference between the strength of reflected lightin the presence of ink and the strength of reflected light in theabsence of ink cannot be broadly divided. In addition, it also resultsin the problem that the device configuration increases in complexitybecause of installing the rod 1001 in the ink tank (i.e., an ink-flowpath of the ink tank). Furthermore, it is difficult to respond toconsumer demands, such as for smaller and cheaper devices, to asufficient degree because of enlarged volume and limited shape of theink tank as a result of arranging the rod therein.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an ink-jet recordingapparatus that performs a detection of the presence or absence of ink ata low cost with reliability.

In a first aspect of the present invention, there is provided a devicefor detecting the presence or absence of a liquid, installed on anink-jet recording apparatus on which a recording head and an ink tankfor supplying ink to the recording head are fixed or removably mounted,comprising:

a light-emitting unit for emitting light to a light transmitting portionhaving at least a part where a ridge portion or groove portion in theshape of V in cross section are formed on the ink tank;

a detecting unit for detecting light which is reflected off the lighttransmitting portion; and

a means for transmitting the results obtained by the detecting unit to acontrol unit of the ink-jet recording apparatus.

In a second aspect of the present invention, there is provided an inktank for supplying an ink to a recording means, which is fixed on orremovably mounted on a recording apparatus for recording an input imageinformation on a recording medium by using the recording means thatejects ink, comprising:

an ink-storing portion for storing ink, provided as an ink-flow path forsupplying ink to the recording means;

a front end portion on which an ink-supplying opening for supplying theink to the recording means;

a rear end portion formed on the other side of the ink tank with respectto the front end portion;

a side surface portion on which a window portion made of alight-transmitting material; and

other side source portions for surrounding the ink-storing portion inconjunction with the side surface portion.

Here, the window portion may be formed by cutting at least a part of theside surface portion into a groove portion in the shape of V in crosssection.

The window portion may be made of at least one ridge portion in theshape of V in cross section.

In a third aspect of the present invention, there is provided arecording apparatus for recording an input image information on arecording medium by using a recording means for ejecting ink,comprising:

a carriage on which an ink tank having a window portion of alight-transmitting material on at least one side surface thereof isfixed or removably mounted;

a device for detecting the presence or absence of a liquid, which arearranged in a position facing to the window portion of the ink tankmounted on the carriage; and

a control unit for determining the presence or absence of ink inaccordance with the results obtained by the device for detecting thepresence or absence of a liquid.

Here, the device for detecting the presence or absence of a liquid maycomprise a light-emitting unit and a light-receiving unit.

The window portion may be formed by cutting at least a part of the sidesurface portion into a groove portion in the shape of V in crosssection.

The window portion may be made of at least one ridge portion in theshape of V in cross section.

The control unit may determine the presence or absence of ink in the inktank in accordance with the presence or absence of a total reflection oflight emitted from the light-emitting unit to the window portion.

The device for detecting the presence or absence of a liquid may be usedas a device for determining whether the ink tank is mounted on thecarriage or not.

The recording means may use an electrothermal transducer for generatingthermal energy required for allowing a phenomenon of film boiling toappear in ink in order to eject ink therefrom.

In a fourth aspect of the present invention, there is provided arecording system, comprising:

an information processing unit for processing input information;

an output unit for recording an output of the information processingunit on a recording medium; and

a control unit for controlling an operating condition of the outputunit, wherein

the output unit having:

a carriage on which an ink tank having a window portion of alight-transmitting material on at least one side surface thereof isfixed or removably mounted;

a device for detecting the presence or absence of a liquid, which arearranged in a position facing to the window portion of the ink tankmounted on the carriage; and

a control unit for determining the presence or absence of ink inaccordance with the results obtained by the device for detecting thepresence or absence of a liquid.

In a fifth aspect of the present invention, there is provided a kitcomprising an ink tank, a recording means to be connected with the inktank, an ink refill means for refilling ink into the ink tank, wherein

the ink tank is for supplying an ink to a recording means, which isfixed on or removably mounted on a recording apparatus for recording aninput image information on a recording medium by using the recordingmeans that ejects ink, and comprises:

an ink-storing portion for storing ink, provided as an ink-flow path forsupplying ink to the recording means;

a front end portion on which an ink-supplying opening for supplying theink to the recording means;

a rear end portion formed on the other side of the ink tank with respectto the front end portion;

a side surface portion on which a window portion made of alight-transmitting material; and

other side source portions for surrounding the ink-storing portion inconjunction with the side surface portion.

In a sixth aspect of the present invention, there is provided a kit,wherein

the recording means is an ink-jet recording head that uses anelectrothermal transducer for generating thermal energy required forallowing a phenomenon of film boiling to appear in ink in order to ejectink therefrom.

In a seventh aspect of the present invention, there is provided arecording unit comprising an ink tank and a recording means to beconnected with the ink tank, wherein

the ink tank is for supplying an ink to a recording means, which isfixed on or removably mounted on a recording apparatus for recording aninput image information on a recording medium by using the recordingmeans that ejects ink, and comprises:

an ink-storing portion for storing ink, provided as an ink-flow path forsupplying ink to the recording means;

a front end portion on which an ink-supplying opening for supplying theink to the recording means;

a rear end portion formed on the other side of the ink tank with respectto the front end portion;

a side surface portion on which a window portion made of alight-transmitting material; and

other side source portions for surrounding the ink-storing portion inconjunction with the side surface portion.

The recording means may be an ink-jet recording head that uses anelectrothermal transducer for generating thermal energy required forallowing a phenomenon of film boiling to appear in ink in order to ejectink therefrom.

In an eighth aspect of the present invention, there is provided a devicefor detecting the presence or absence of a liquid, installed on anink-jet recording apparatus on which a recording head and an ink tankfor supplying ink to the recording head are fixed or removably mounted,comprising:

a window portion formed on at least a part of a wall of the ink tank;

a light-emitting unit for emitting light to the window portion; and

a light-receptor unit for receiving light which is reflected off aninner wall surface of the window portion after emitting from thelight-emitting unit, wherein

a shape of the inner wall surface of the window portion is differentfrom a shape of an inner wall surface of the ink tank around the windowportion.

Here, the inner surface of the window portion may be shaped so as tointroduce light emitted from the light-emitting unit into an interfacebetween the ink and the ink tank at a predetermined angle, and

the light-receptor unit is positioned on a path of light reflected fromthe interface between the ink and the ink tank after emitting from thelight-emitting unit.

The light-emitting unit may be positioned so as to introduce light intothe window portion, perpendicularly.

The inner wall surface of the window portion may be shaped so as tointroduce incident light from the light-emitting unit into the interfaceof the ink and the ink tank at an angle of 45° C.

In the following description, the term "recording" means that all kindsof the procedure for proving ink on ink supports such as cloth, yarn,paper, and other sheet materials (i.e., printing process, image-formingprocess, copying process, dye or staining process, and the like).Therefore the field of the invention is not limited to the field ofinformation-processing, and so it is also applicable to other fieldsincluding apparel industries using the ink supports for receiving inksuch as cloth, yarn, paper, and other sheet materials.

The above and other objects, effects, features and advantages of thepresent invention will become more apparent from the followingdescription of embodiments thereof taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a conventional device fordetecting the presence or absence of a liquid in a container;

FIG. 2 is a perspective illustration of a recording unit to be mountedon an ink-jet recording apparatus in accordance with the presentinvention;

FIG. 3 is a schematic illustration of a window portion of an ink tankand a device for detecting the presence or absence of ink, where thedevice comprises a light-emitting unit to emit light to the windowportion and a light-receiving unit to detect reflected light;

FIG. 4 is a schematic illustration of a carriage and a carriage-guideshaft for slidably supporting the carriage to be applied in an ink-jetrecording apparatus of the present invention, where the carriage movesalong the carriage-guide shaft in the main-scanning direction;

FIG. 5 is a block diagram of electric circuit to be applied in anink-jet recording apparatus of the present invention;

FIG. 6 is a cross-sectional view of an ink tank and a device fordetecting the presence or absence of ink to be applied in an ink-jetrecording apparatus as one of the preferred embodiments of the presentinvention;

FIG. 7 is a schematic cross-sectional view of an ink tank and a devicefor detecting the presence or absence of ink to be applied in an ink-jetrecording apparatus as one of the preferred embodiments of the presentinvention;

FIG. 8 is a schematic cross-sectional view of an ink tank and a devicefor detecting the presence or absence of ink to be applied in an ink-jetrecording apparatus as one of the preferred embodiments of the presentinvention;

FIG. 9 is a perspective illustration of a recording unit to be mountedon an ink-jet recording apparatus as one of the preferred embodiments ofthe present invention;

FIG. 10 is a schematic illustration of a carriage configuration in whicha recording unit having an ink-jet recording head and an ink tank ismounted on the carriage;

FIG. 11 is a perspective diagram of an ink-jet recording apparatus asone of the preferred embodiments of the present invention;

FIG. 12 is a perspective diagram of an information-processing system asone of the preferred embodiments of the present invention; and

FIG. 13 is an ink-jet head kit comprising a recording head unit and anink refill device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An ink tank as an ink-holding member to be mounted in a recordingapparatus according to the present invention, comprises an ink-storingchamber, a front end portion in which an ink-supplying portion is formedfor supplying ink to a recording means (hereinafter, also referred as arecording head) connected therewith, a posterior end portion in which anair-communicating port is formed to make a communication between theabove ink-holding means and the air, a side wall portion (hereinafter,referred as an ink-flow path parallel to a direction of supplying ink tothe recording head, and a window made of a light-transmitting materialon a front end side of the side wall portion. According to the presentinvention, furthermore, a device for detecting the presence or absenceof a liquid is installed in the recording apparatus for detecting thepresence or absence of the remaining ink in the tank. Preferredembodiments of the present invention will be described below in aconcrete manner.

<Embodiment 1>

FIG. 2 is a perspective illustration of a recording unit to be mountedon an ink-jet recording apparatus in accordance with the presentinvention. The recording unit has a single-piece construction in whichan ink-jet recording head 20 is integral with an ink tank 21 in aremovable manner.

The ink-jet recording head 20 comprises an ink inlet portion 20a and anink ejecting portion 20c communicated therewith. In this embodiment, theink-jet recording head 20 uses electro-thermal conversion elements(hereinafter, referred as heaters) as energy-generating means. As aresult, a bubble is formed in the ink by a pulse of an electric drivesignal provided from the system unit of the ink-jet recording apparatus,and in an instant the growth and collapse of the bubble occurs in asuitable manner, resulting that it is particularly suited for anejection of ink-droplet because of significant response propertiesthereof. Thus, it is possible to make the ink-jet recording head easilyas compact as possible by using the electro-thermal converting elementsas the energy generating means. Another advantage is that the recordinghead using the electro-thermal conversion elements can be fullyfabricated with a process utilizing technical advances made in thesemiconductor fields in recent years and technical merits of IC andmicrofabrication technologies with remarkable technical advances andimproved reliabilities, thus making high density fabrication easy andreducing manufacture cost in addition to further miniaturization of therecording head.

On the other hand, the ink tank 21 comprises an ink-holding chamber 2for reserving ink to be supplied to the ink-jet recording head 20 and anopening as an ink outlet portion 21b formed on a front end portionthereof into which an ink inlet portion 21a of the ink-jet recordinghead 20 can be fitted. As shown in the figure, there is a pair ofprojections 21d from the front end and they have hooks on their freeends so as to be able to engage in a pair of holes 20b formed on the endportion of the ink-jet recording head 20 from which the ink-inletportion 20b is protruded. Furthermore, at least one side surface (i.e.,an ink-flow wall) 21c of the ink tank 21 is made of a transparentmaterial (e.g., transparent plastics and glasses), and also a groovedportion is formed on the front side thereof. Or to put it another way:the grooved portion is formed as a rise of an inner side of the ink tank21 so as to have a V-shaped cross section. In this embodiment,therefore, the grooved portion is provided as a window having twoinclined surfaces 1a, 1b.

For illustrating the ink tank in brief, an ink-induction member and anink-absorbing member are not shown in the figure. This embodiment,however, is not limited to such configuration. It is also possible toprovide other configurations of the ink tank having such window, forexample one having the ink-induction member and the ink-absorbingmember, or of separating the ink-holding chamber into two parts (i.e.,one for keeping these members and the other for keeping ink). The windowmay be positioned in accordance the construction of the ink tank.

FIG. 3 is a schematic illustration of the window of the ink tank shownin FIG. 2 and an ink-detecting assembly for detecting the presence orabsence of ink in the ink tank. The components that make up the assemblyinclude a photo-emitting member 10 for illuminating light toward thewindow 1 of the ink tank 21 and a photo-receptor member 11 for detectingreflected light.

The ink-detecting assembly can be positioned so as to face to the abovewindow 1 when it is mounted on a carriage of the ink-jet recordingapparatus (or a recording unit is positioned at a home positionthereof).

The photo-emitting member 10 is in the type of a high directivity andgenerates a beam of light substantially without an attenuation thereofin the ink. Thus the photo-emitting member 10 may be an illuminationelement having a light-gathering power by means of a lens or the likewith respect to infrared light or near infrared light to illuminate abeam of light with a high directivity. The beam of light emitted fromthe photo-emitting member 10 is introduced into the inclined surface 1aat a substantially constant angle θin.

In this embodiment, by the way, the components of ink stored in the inkholding chamber 2 include glycol, alcohol, dye stuff, and the like inaddition to 80% or more of water. This kind of ink has a refractiveindex n-ink of 1.3 to 1.4, almost the same order as that of water. Onthe other hand, the wall of ink-flow path may be made of a transparentplastic or grass material, having a refractive index n-wall of 1.5 to1.6. In addition, the air has a refractive index n-air of approximately1.0003. Therefore, in the case that a substantial amount of ink is foundin the ink flow path, a critical angle θ1 to cause a total reflectionagainst the incident light at the inclined surface 1a can be calculatedby the following formula (1) and results in the critical angle θ1 of 54to 69.

    sin(θ1)=n-ink/n-wall=(1.5˜1.6)/(1.3˜1.4) (1)

In the case of the absence of ink in the ink flow path, a critical angleθ2 to cause a total reflection against the incident light at theinclined surface 1a can be calculated by the following formula (1) andresults in the critical angle θ2 of 39 to 42.

    sin(θ2)=n-air/n-wall=1.003/(1.5˜1.6)           (2)

In the case that the incident angle θin to the inclined surface 1a is inthe range of 43 to 53, consequently, a total reflection cannot occur inthe presence of ink while it can occur in the absence of ink. Thus thepresent embodiment is configured to define the incident angle θin=45°.Accordingly, in the case that a substantial amount of the ink is presentin the tank the incident light passes through the window 1 and travelsalong a light path 3. In the case that a substantial amount of the inkis not present in the tank, on the other hand, the incident light doesnot pass through the window 1, while it is reflected from the inclinedsurface 1a and travels along a light path 4. Then the light passingthrough the light path 4 is total-reflected by the inclined surface 1band then travels along the light path 5 extending to the photo-receptormember 11.

The presence or absence of ink in the ink path can be detected withstability according to the relationship among the light intensitiesindicated by the following inequality:

    A>B>C

wherein A represents an intensity of the light detected by thephoto-receptor member 11 when the ink is not present in the ink path, Brepresents an intensity of the light detected by the photo-receptormember 11 when the ink is present in the ink path, and C represents anintensity of the light detected by the photo-receptor member 11 when theink path is not found (i.e., the ink tank is not mounted on thecarriage). The difference between A and B is comparatively large, sothat the presence or absence of ink in the ink path can be detected withstability by the differences among the light-intensities of the lightintroduced into the photo-receptor portion 11. In this case, by the way,the difference between B and C is comparatively small. However, thedetection of the presence or absence of ink in the ink tank can beperformed by improving the detection-sensitivities of the photo-receptor11.

In the figure, "h" represents a height of an ink surface at the positionlower than the tip 1c of the V-shaped portion formed on the window 1,where the light beam from the photo-emitting member 10 comes intocontact with the inclined surface 1a. A total reflection of the lightbeam can occur when the ink surface is lower than h by consuming theink, so that h is responsible for determining a detection point forregarding the ink-path (or the ink tank) as empty whether a small amountof ink is being remained or not. Therefore it is possible to change theabove height h by shifting the position of the photo-emitting portion 10to shift a point on which the light beam from the photo-emitting portion10 comes contact with the inclined surface 1a.

In the figure, reference numeral 12 is a douser for preventing theincident of light from the photo-emitting portion 10 to thephoto-receptor portion 11, by which the reflected beam can be detectedwith stability when the photo-emitting portion 10 consists of a cheepphoto-emitting element such as a light-emitting diode (LED). Forimproving the straight-traveling properties of light, furthermore, thelight emitted from the light-emitting member 10 may be introduced intothe ink-flow path after passing through a slit (not shown) to travel ina straight line. A hydrophilic treatment may be performed on theink-flow wall for preventing a deposition of bubbles thereon witheffect.

By the way, the present invention is configured to utilize a refractiveindex of the ink, so that the results of the detection described aboveis hardly susceptible to the variations in colors of ink. It means thatthe above means for detecting the presence or absence of ink in the inkpath can be utilized in a color printer or the like, with respect to allof different colors used therein.

FIG. 4 is a schematic illustration of a carriage 22 and acarriage-guiding axis 23. As described above, the recording unit has asingle-piece construction in which an ink-jet recording head 20 isintegral with an ink tank 21 in a removable manner. The carriage-guidingaxis 23 is responsible to hold the carriage in a slidable manner, onwhich the carriage moves in the sub-scanning direction.

The ink-jet recording head 20 has a positioning portion (not shown) anda flexible base board (electric connecting portion) for electricallyconnecting to the carriage 22. By using such devices, therefore, theink-jet recording head 20 can be mounted on the carriage 22 with anelectric connection therebetween.

An electric circuit of the ink-jet recording apparatus is constructed asdescribed in the follows and shown in a block diagram of FIG. 5. In thefigure, the same components as illustrated in the other figures areindicated by the same reference numerals, and also their duplicatedexplanations are eliminated in the following description. In the figure,furthermore, reference numeral 401 denotes a controller as a maincontrol unit, 402 denotes, a central processing unit (CPU) in the shapeof one used in, for example a micro-computer, 403 denotes a randomaccess memory (RAM) having a region for expanding text data or imagedata, a work region, and so on, 404 denotes a read only memory (ROM) inwhich stationary data such as program data and font data are stored, 405denotes a timer responsible for making execution cycles of the CPU 402and for producing timings to be required in a recording movement by theprinter unit, and 406 denotes an interface portion for connectingsignals of the CPU 402 with the peripheral devices. Furthermore,reference numeral 407 denotes a controller of the printer unit 407, and11 denotes a light-receptor unit shown in FIG. 2. Reference numeral 408denotes an ink tank sensor for making sure the presence or absence ofthe ink tank, 409 denotes a head driver for sending recording signals,electric powers, and so on to the ink-jet recording head 20, 410a, b,and c denote motor drivers for sending signals, electric powers, and soon to be required for motors of moving the carriage, feeding therecording paper, driving the recovering system, and so on, respectively,411 denotes a carriage sensor for detecting a location of the carriageand determining, for example whether the carriage is located at a homeposition or not, 412 denotes a paper sensor for detecting the presenceor absence of a sheet of paper to avoid a recording on non-recordingareas thereof or other components when the recording paper is notappropriately provided or when a last sheet of paper is recorded.

In the configuration described above, a warning against the remainingquantity is performed if the ink detecting unit detects the absence ofink in the ink tank. In this case, the remaining quantity of ink in theink tank can be estimated almost accurately at the time of detecting theabsence of ink in the ink tank (i.e., at the time of warning against theremaining quantity) because the detecting means comes to a conclusionthat the ink is absent when the ink surface is under the predeterminedink level. Therefore, it may be configured so as to output an ink-lesserror after determining that the amount of ink consumed is reached atthe predetermined level by calculating the consumption of ink at theevents of recording, primary ejection, absorption, and the like whichare performed after the output of ink-less error. Furthermore, it may bealso configured so as to inhibit the movements of recording, absorbing,and the like after the output of ink-less error. The data concerned withthe remaining quantity of the ink is stored in the RAM 402 describedabove, and so it is preferable that the RAM 402 is in the type ofnonvolatile.

<Embodiment 2>

FIG. 6 is a schematic section view of an ink tank and an ink-detectingunit of the ink-jet recording apparatus as a second preferred embodimentof the present invention. An ink-flow wall 501 has a plurality ofinclined surfaces 501a formed as a sawtooth in cross section. Therefore,it is configured to perform a stable detection of total reflected lightor transmitted light depended on the presence or absence of ink at theinclined surfaces 501a in the event that the light emitted from thelight-emitting unit 510 is diffused to an extent. The light emitted fromthe light-emitting unit 510 is introduced into a plurality of theinclined surfaces 501a. If the ink is in the ink-flow path 502, thelight passes through the inclined surfaces 501a and then travels along alight path 503. If the ink-flow path 502 holds no ink but the air, theinclined surfaces 501a reflect the light perfectly and the reflectedlight travels along a light path 504. By the construction shown in FIG.6, furthermore, it is possible to change the height of the inclinedsurfaces 501a to meet the user's needs. In addition, there is nopossibility of generating any irregular of the light reflection to becaused by a scratch on an inclined portion because a plurality of theinclined surfaces 502 is formed in an inner side of the ink tank.

<Embodiment 3>

FIG. 7 is a schematic section view of an ink tank and an ink-detectingunit of the ink-jet recording apparatus as a third preferred embodimentof the present invention. An inclined surface 61a is formed on a corner(at a front-end side) of an ink-flow wall 601, so that an ink tank canbe provided as of a simple shape so as to have a high degree offlexibility in formation of the inclined surface at an appropriateportion.

<Embodiment 4>

FIG. 8 is a schematic section view of an ink tank and an ink-detectingunit of the ink-jet recording apparatus as another preferred embodimentof the present invention. Inclined surfaces 701a, 701b are formed on theother side of the ink-flow wall 701 with respect to the ink-flow path702. A light-emitting unit 710 is positioned so that the inclinedsurface 701a is almost perpendicular to the incident light, i.e., thelight emitted from the light-emitting unit 710 enters into the inclinedsurface 701a, almost perpendicularly. On the other hand, alight-receptor unit 711 is positioned so that the inclined surface 701bis on a path of the total reflected light. In this case, there is noneed to provide the inclined surface 701b as a plane perpendicular tothe light path, but a detection without an influence of the reflectionindex of the light can be performed more stable as the relationshipbetween the light path and the inclined surface 701b get closer to aright angle.

<Embodiment 5>

FIG. 9 is a schematic section view of an ink-jet unit to be mounted onthe ink-jet recording apparatus as another preferred embodiment of thepresent invention.

The inclined surfaces 801a, 801b are formed on a side surface of an inktank 821. In addition, a light-reflective portion 810 is also formed onthe same side surface.

FIG. 10 is a schematic illustration of a carriage on which the ink-jetunit having the ink-jet recording head and the ink tank shown in FIG. 9is mounted. In the figure, reference numeral 810 denotes a photosensorunit as a combination of light-emitting portion and a light-receptorportion. The photosensor 810 is installed on a fixed portion formed onan outside of the carriage 822. When the carriage 822 travels along thecarriage guide axis 823, the inclined surfaces 801a, 801b of the inktank 821 and the light-reflective portion 801c face to the photosensorportion 810, respectively, according to the shifted positions of thecarriage 822. Therefore, the absence or presence of the ink can bedetected by facing the photosensor portion 810 to the inclined surfaces801a, 801b, while the absence or presence of the ink tank on thecarriage can be detected by facing the photosensor portion 810 to thelight-reflective portion 801c. It means that the absence or presence ofthe ink and the absence or presence of the ink tank are detected byusing only one common photoreceptor. By forming each surface of the inktank as impenetrable by light except the inclined surfaces 801a, 801b,the light passes only through the inclined surfaces 801a, 801b. When theinclined surfaces 801a, 801b are covered with the ink (i.e., the inklevel is higher than their positions), they do not reflect the incidentlight and so an inner side of the ink tank can be seen as a dark placeby making visual observations through the surfaces 801a, 801b. When theinclined surfaces 801a, 801b are clear of the ink (i.e., the ink levelis lower than their positions), they reflect the incident light and soan inner side of the ink tank can be seen as a light place by makingvisual observations through the surfaces 801a, 801b. Consequently, theabsence or presence of the ink in the ink tank can be determined byobserving those conditions. In the case that the incident light shouldbe cut off from the ink tank, the absence or presence of the ink can bealso detected by observing through the inclined surfaces.

<Other embodiments>

A general construction of the ink-jet recording apparatus on which theink tank and the ink detecting unit of one of the above embodiments 1 to5 are mounted will be described below with reference to FIG. 11.

FIG. 11 is a schematic illustration of an ink-jet recording apparatus asone of the preferred embodiments of the present invention.

An ink-jet recording apparatus IJRA has a lead screw 2040 that rotatesby working together with a normal or reverse rotation of a driving motor2010 through a set of transmission gears 2020, 2030. A carriage HC onwhich an ink-jet cartridge is mounted is supported by a carriage shaft2050 and the lead screw 2040. Also, the carriage has a pin (not shown)to be engaged in a spiral groove 2041 formed on a peripheral surface ofthe lead screw 2040 so as to move back and forth in the directions shownby the arrows a, b.

Reference numeral 2060 denotes a platen plate that positions the paper Pand holds it against a platen roller 2070 in the direction of moving thecarriage. Reference numeral 2080 and 2090 are photocouplers to be usedas a home-position detecting means for changing a rotational directionof the motor 2010, and so on by recognizing that a lever 2100 arrangedon the carriage HC is located at the position of these photocouplers.

A head recovering unit comprising a capping member 2110 and a suckingmember 2130 is arranged at the position facing to one end of the path ofdisplacement of the carriage HC, e.g., the position located opposite toa home position of the ink-jet cartridge IJC. As the driving forcegenerated by the motor 2010 is transmitted via the power transmittinggears 2020, 2030, the head recovering unit is activated to cap therecording head with the cap member 2110 supported by a supporting member2120. Subsequently, ink is sucked (to attain suction recovery) bydriving the sucking member (e.g., suction pump) 2130 disposed in thehead recovering unit in operative association with the capping member2110, whereby ink located in the ink ejecting ports of the recordinghead with increased viscosity is forcibly discharged from the inkejecting ports.

Reference numeral 2140 designates a cleaning blade for wiping anejection surface of the recording head and it is held by a blade holdingmember 2160 so as to move back and forth. These members are arranged ona supporting plate 2160 of a main body.

Reference numeral 2170 designates a lever for starting a suctionrecovery. The lever 2170 moves with a movement of cam engaged with thecarriage HC to control a driving force of the motor 2010 by producingvariable or reciprocating motion in parts of transmission mechanism suchas a clutch shifter.

Since a recording apparatus including an ink-jet recording head of theforegoing type makes it possible to perform a recording operation notonly at a high density but also at a high speed, it is utilized andcommercialized as outputting means for a recording system, e.g., aprinter serving as an output terminal unit for a copying machine, afacsimile, an electronic typewriter, a word processor, a work station orthe like or a handy or portable type printer to be equipped in aninformation processing system such as a personal computer, a hostcomputer, an optical disc unit, a video unit or the like. In thecircumstances as mentioned above, an ink-jet recording apparatus isconstructed in such a manner as to match with a function and a type ofpractical use inherent to each of the aforementioned units.

In the case of a color ink-jet recording apparatus for printing in twoor more colors, a multicolor image is formed by allowing ink droplets tooverlap one above another on a recording medium by ejecting inks ofseveral colors from a plurality of color ink-jet recording heads or byan arrangement of colors into rows and columns of a matrix (N×N) on therecording medium. Generally, in the case that a color recordingoperation is performed with the color ink-jet recording apparatus, threeor four ink-jet recording heads and three or four ink cartridgescorresponding to three primary colors composed of yellow (Y), magenta(M) and cyan (C) or four colors composed of three primary colors andblack (B). Lately, a color ink-jet recording apparatus having three orfour kinds of color ink-jet recording heads mounted thereon so as toenable an image to be formed with full color has been put in practicaluse.

In addition, the foregoing type of color ink-jet recording apparatus canbe constructed in such a manner as to enable an image to becomparatively easily recorded on a recording medium with a size of"A-1". Concretely, a color ink-jet recording apparatus electricallyconnected to a reader adapted to read a A-1 sized original of multicolorimage so as to allow the original to be recorded on a recording paper,e.g., a plotter serving as a CAD output printer has been commercialized.On the other hand, it is practically required that the color ink-jetrecording apparatus can be used in a variety of fashions, and lately,requests have been increasingly raised from users for providing a colorink-jet recording apparatus capable of recording various kinds ofinformation such as characters, graphs, pictures, and figures on an OHPfilm in order to visually project the information on a screen for thepresentation in a conference or lecture.

We are now explaining a recording system that performs a recording on arecording medium by using a liquid-ejecting head as a recording head.

FIG. 12 is a schematic illustration of the recording system as apreferred embodiment of the present invention. In this embodiment, aliquid-ejection head is of a full-line type with a length thereofcorresponding to a recording width of the recording medium 150. Theliquid-ejection head comprises a plurality of orifices with pitches of360 dpi in the direction of length. In the liquid-ejection head, thereis a holder 202 for folding four heads corresponding to four differentcolors: yellow (Y), magenta (M), cyan (C), and black (Bk), respectively.These color heads are arranged in parallel with predetermined spacing inthe direction of arrow X.

Each of these color heads receives signals from a head driver 307comprised in the driving signal supplying means, and thus they aredriven according to their corresponding signals, respectively. Inaddition, the color heads receive color ink of Y, M, C, and Bk from inktanks 204a-204d, respectively.

Furthermore, reference numeral 204e denotes a container for storing ablowing solution, so that each of the color heads is configured toreceive a supply of the blowing solution from the container 204e. Inthis embodiment, these ink tanks 204a-204d and the container 204e havewindow portions (not shown) as the same as any one of the aboveembodiments 1 to 5. The window portion of each tank or container isarranged so as to face to a corresponding device for determining theabsence or presence of a liquid.

Head caps 203a-203d, in which ink-absorbing materials such as spongesare imbedded, are arranged below the color heads, respectively, fortheir protection by covering each head with each corresponding head capat the period of non-recording.

Reference numeral 206 denotes a feed belt as a means for transmittingthe recording material. The feed belt is routed round various kinds ofrollers in a predetermined path and driven by a drive roller connectedwith a motor driver 305.

In the recording system of the present embodiment, various kinds oftreatments can be down on the recording medium, before and after therecording. Thus the recording system comprises a pre-treatment device251 for treating the recording medium prior to the step of recording anda post-treatment device 252 for treating the recording medium subsequentto the step of recording. The pre-treatment device 251 is arranged inthe downstream of a path of feeding the recording medium, while thepost-treatment device 252 is arranged in the upstream thereof.

The contents of the pre- and post-treatments are varied according to thevariations of ink or recording media to be used for the recordingprocess, for example the application of UV and ozone is performed on arecording medium made of metal, plastic, ceramic, or the like toactivate a surface thereof for improving the adherence. In the case ofusing a recording medium having a static-prone surface, such as a sheetof plastic material, debris may be easily to adhere thereon to preventthe formation of an excellent image by the contaminated surface. Therecording medium may be guarded against static buildup with an ionizeras the pre-treatment to remove the debris from the recording medium. Inthe case of using a textile- or fabric-based recording medium, it ispreferable to perform a pre-treatment of one selected from the group ofalkaline materials, water-soluble materials, synthetic polymers,water-soluble metallic salts, urea, and thiourea from the points of, forexample preventing shrinkage and improving the degree of exhaustion. Itis noted that the pre-treatment procedures are not restricted by theabove ways. It is also possible to adopt other procedures, for example apre-treatment having the step of heating the recording medium at atemperature preferable to the recording.

For the post-treatment, on the other hand, there are several treatmentscan be performed, for example: a fixation for fixing ink applied on therecording medium by means of UV irradiation or by means of heat; and awashing fro removing a remaining unreact material used in thepre-treatment.

Accordingly, the ink-jet recording apparatus of the present inventioncan be used as one superior to the others in many industrial fields(e.g., apparel industries) and provides images with excellent imagequalities compared with that of the conventional one.

By the way, as described above, the ink tank can be removably connectedwith the ink-jet recording head to form a recording unit in a one-piecedesign. Thus it can be introduced in the market. In accordance with thepresent invention, therefore it is also possible to provide an inkrefill means for replenishing the ink tank with ink.

FIG. 13 is a schematic illustration of an ink-jet head kit provided as aset of a recording unit and an ink refill device. That is, a kitcontainer 501 comprises an ink-jet recording head 510 having an inkejection portion 511 for ejecting ink, an ink tank 520 as a liquidcontainer which is stationary or removably connected with the ink head510, and an ink refill device 530 for refilling ink into the ink tank510.

After using the ink up, ink may be refilled in the ink tank through aninsert portion (e.g., injection needle) 531 of the ink refill device.That is, the insert portion 531 of the ink refill device is insertedinto a hole made on a wall or an air communicating port 521 of the inktank, or a connected portion between the ink tank and the recordinghead.

In accordance with the present invention, as described above, theink-jet kit combines the ink-jet recording head, the ink tank having theconfiguration of one of the above embodiments, and the ink refill deviceinto a container of compact design. In the case of using the ink up,therefore, the recording can be easily carried out again without muchtimes by refilling ink into the ink tank by using the above kit.

As explained above, the device for detecting the presence or absence ofa liquid, ink tank, kit, recording unit, recording apparatus, andrecording system constructed by the connection with the informationprocessing device of the present invention are configured to determinethe presence or absence of ink in the ink flow path by detecting thereflection of light from a light transmission portion by irradiatinglight thereon. The light transmission portion is formed on at least apart of the ink path wall that forms the ink flow path for supplying inkto the recording head. As a result, it becomes possible for respondingto consumer demands of designing a smaller version of the ink tank, acost effective production thereof, and the like in addition to provideimages with excellent image qualities.

The present invention has been described in detail with respect topreferred embodiments, and it will now be apparent from the foregoing tothose skilled in the art that changes and modifications may be madewithout departing from the invention in its broader aspects, and it isthe intention, therefore, in the appended claims to cover all suchchanges and modifications as fall within the true spirit of theinvention.

What is claimed is:
 1. A ink let recording apparatus for recording inputimage information on a recording medium by using a recording means forejecting ink supplied from an ink tank storing ink, said apparatuscomprising:a detecting means having a light-emitting element foremitting light and a light-receiving unit for producing an outputaccording to an amount of received light; a carriage on which said inktank is mountable, said ink tank having: a first detecting portion onwhich an amount of reflected light changes according to a presence orabsence of ink in said ink tank, the first detecting portion beingarranged at a predetermined position on a wall of said ink tank; and asecond detecting portion reflecting a comparatively larger amount oflight, the second detecting portion being arranged at a positiondifferent from that of the first detecting portion; a carriage-movingmeans for moving said carriage, by which a relative position betweensaid carriage and said detecting means is changed according to themovement of said carriage; and a control unit for detecting a drop in aremaining quantity of ink in said ink tank by detecting the output ofsaid detecting means when said carriage and said detecting means arepositioned at a first relative position as a result of movement of saidcarriage by said carriage-moving means, and determines the absence orpresence of said ink tank on said carriage by detecting the output ofsaid detecting means when said carriage and said detecting means arepositioned at a second relative position, wherein the first relativeposition is a position in which the first detecting portion of said inktank to be mounted on said carriage faces said detecting means; and thesecond relative position is a position in which the second detectingportion of said ink tank to be mounted on said carriage faces saiddetecting means.
 2. An ink jet recording apparatus as claimed in claim1, wherein:the first detecting portion is a window portion made of alight transmissive material; and said window portion is formed bycutting at least a part of a side surface portion of said ink tank intoa groove portion having a V-shaped cross section.
 3. An ink jetrecording apparatus as claimed in claim 1, wherein:the first detectingportion is a window portion made of a light transmissive material; andsaid window portion is made of at least one edge portion of said inktank having a V-shaped cross section.
 4. An ink jet recording apparatusas claimed in claim 1, wherein said control unit determines a drop inthe remaining quantity of ink in said ink tank according to the amountof reflected light exposed on the first detecting portion by thelight-emitting element.
 5. An ink jet recording apparatus as claimed inclaim 1, wherein said control unit allows the emission of light by thelight-emitting element at the second relative position and determineswhether or not said ink tank is mounted on said carriage according tothe amount of reflected light exposed on the second detecting portion bythe light-emitting element.
 6. An ink jet recording apparatus as claimedin claim 1, wherein said recording means uses an electrothermaltransducer for generating thermal energy required for allowing aphenomenon of film boiling to appear in ink in order to eject inktherefrom.
 7. A recording system, comprising:an information processingunit for processing input information; an output unit for recording anoutput of said information processing unit on a recording medium; and acontrol unit for controlling an operating condition of said output unit,wherein said output unit has: a detecting means having a light-emittingelement for emitting light and a light-receiving unit for producing anoutput according to an amount of received light; a carriage on which anink tank for storing ink is mountable, said ink tank having: a firstdetecting portion on which an amount of reflected light changesaccording to a presence or absence of ink in said ink tank, the firstdetecting portion being arranged at a predetermined position on a wallof said ink tank; and a second detecting portion reflecting acomparatively larger amount of light, the second detecting portion beingarranged at a position different from that of the first detectingportion; a carriage-moving means for moving said carriage, by which arelative position between said carriage and said detecting means ischanged according to the movement of said carriage; and a second controlunit for detecting a drop in a remaining quantity of ink in said inktank by detecting the output of said detecting means when said carriageand said detecting means are positioned at a first relative position asa result of movement of said carriage by said carriage-moving means, anddetermines the absence or presence of said ink tank on said carriage bydetecting the output of said detecting means when said carriage and saiddetecting means are positioned at a second relative position, whereinthe first relative position is a position in which the first detectingportion of said ink tank to be mounted on said carriage faces saiddetecting means; and the second relative position is a position in whichthe second detecting portion of said ink tank to be mounted on saidcarriage faces said detecting means.
 8. A device for detecting thepresence or absence of a liquid, installed on an ink-jet recordingapparatus on which a recording head and an ink tank for supplying ink tosaid recording head are fixed or removably mounted, comprising:alight-emitting unit for emitting light to a window portion; and alight-receptor unit for receiving light which is reflected off an innerwall surface of said window portion after emitting from saidlight-emitting unit, wherein said window portion is formed on at least apart of a wall of said ink tank, a shape of said inner wall surface ofsaid window portion is different from a shape of an inner wall surfaceof said ink tank around said window portion, a reflection portion with areflectivity of light is greater than that of the wall of said ink tank,said reflection portion being formed on at least one portion of the wallof said ink tank, a remaining quantity of an output of ink in said inktank is detected in accordance with an output of said light-receptorunit at a position where said light-emitting unit and said lightreceptor unit are directed to said window portion, and a mounting stateof said ink tank is determined in accordance with an output of saidlight-receptor unit at a position where said light emitting unit andsaid light receptor unit are directed to a reflection portion of saidink tank.
 9. A device for detecting the presence or absence of a liquid,as claimed in claim 8, whereinsaid inner wall surface of said windowportion is shaped so as to introduce light emitted from saidlight-emitting unit into an interface between said ink and said ink tankat a predetermined angle, and said light-receptor unit is positioned ona path of light reflected from said interface between said ink and saidink tank after emitting from said light-emitting unit.
 10. A device fordetecting the presence or absence of a liquid, as claimed in claim 8,whereinsaid light-emitting unit is positioned so as to introduce lightinto said window portion, perpendicularly.
 11. A device for detectingthe presence or absence of a liquid, as claimed in claim 10, whereinsaidinner wall surface of said window portion is shaped so as to introduceincident light from said light-emitting unit into said interface of saidink and said ink tank at an angle of 45°.